Start a dedicated thread per client.

Frameworks/MQTTnet.NetStandard/Server/MqttServer.cs

@@ -156,9 +156,11 @@ namespace MQTTnet.Server
 
         private void OnClientAccepted(object sender, MqttServerAdapterClientAcceptedEventArgs eventArgs)
         {
-            eventArgs.SessionTask = Task.Run(
+            eventArgs.SessionTask = Task.Factory.StartNew(
                 () => _clientSessionsManager.RunSessionAsync(eventArgs.Client, _cancellationTokenSource.Token),
-                _cancellationTokenSource.Token);
+                _cancellationTokenSource.Token,
+                TaskCreationOptions.LongRunning, 
+                TaskScheduler.Current);
         }
     }
 }

Frameworks/MQTTnet.Netstandard/MQTTnet.NetStandard.csproj

@@ -22,7 +22,7 @@
     <CopyLocalLockFileAssemblies>false</CopyLocalLockFileAssemblies>
     <NugetTargetMoniker>UAP,Version=v10.0</NugetTargetMoniker>
     <TargetPlatformIdentifier>UAP</TargetPlatformIdentifier>
-    <TargetPlatformVersion>10.0.16299.0</TargetPlatformVersion>
+    <TargetPlatformVersion>10.0.17134.0</TargetPlatformVersion>
     <TargetPlatformMinVersion>10.0.10240.0</TargetPlatformMinVersion>
     <TargetFrameworkIdentifier>.NETCore</TargetFrameworkIdentifier>
     <TargetFrameworkVersion>v5.0</TargetFrameworkVersion>
@@ -56,7 +56,7 @@
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)'=='uap10.0'">
-    <PackageReference Include="Microsoft.NETCore.UniversalWindowsPlatform" Version="6.0.8" />
+    <PackageReference Include="Microsoft.NETCore.UniversalWindowsPlatform" Version="6.1.4" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)'=='net452'">